The oratory (St George Chapel) was erected in 1377-78 next to the Basilica del Santo, in front of the church and on the south side of the piazza, which at that time served as a cemetery. It was commissioned by Raimondino de' Lupi, one of the marchesi of Soragna as his family funeral chapel and it was completed by Bonifacio de' Lupi, his executor. The marchesi of Soragna came from the region of Parma and lived as exiles in Padua, where, along with the Carrara, they were among the most important families.

Even before Raimondino, Bonifacio had arranged for the construction of a large burial chapel dedicated to St James in the Basilica del Santo (the Cappella San Giacomo). This chapel was begun in 1372 in a privileged location inside the basilica opposite the Chapel of St Anthony (Cappella di Sant'Antonio) and was completed, along with its painted decoration, in 1379. The fresco decoration is essentially the work of Altichiero with the assistance of the Bolognese painter Jacopo Avanzi.

Immediately after the frescoes in the St James Chapel were completed, Altichiero was commissioned by Raimondino de' Lupi to decorate the St George Chapel. The artist received the last payment for this work in 1384. These frescoes - the artist's principal work - have suffered considerably over the course of the centuries. They were whitewashed during the period of the Napoleonic wars and rediscovered in 1837.

Both the architecture and the system of decoration is strikingly reminiscent of the Scrovegni Chapel, completed about eighty years earlier. As the Scrovegni Chapel, the oratory has a small brick façade and the interior has a single nave with barrel vault frescoed with a starry sky and the walls divided by artificial architectural frames to organize the stories depicted. Unlike the Scrovegni Chapel, however, the pictorial fields here are of varying sizes, partly because of the positions of the windows, and partly owing to the subject matter of the pictures. A further difference can be found in the lack of uniformity in the pictorial program.

The frescoes on the entry (northeast) and altar (southeast) walls are dedicated to Christ and to Mary, and those on the longitudinal walls are devoted to saints, St George (northeast wall) and Sts Lucy and Catherine of Alexandria (southwest).

On the entry wall the story of Christ's childhood is depicted. Following the Annunciation (top) are the Adoration of the Shepherds (middle left), the Adoration of the Magi (middle right), The Flight into Egypt (bottom left) and the Presentation in the Temple (bottom right). The two pictures on the altar wall represents the Coronation of the Virgin (top) and the Crucifixion (bottom).

Six of the seven paintings on the northeast wall (left to the entrance) are devoted to the life and martyrdom of St George. On the southwest wall opposite the St George cycle are four scenes depicting the work and martyrdom of St Catherine (in the upper register) and that of St Lucy (in the lower register).

The pictorial program that unfolds on the walls was supplemented in the vault, which is subdivided into three sections via three figures - no longer surviving - set in mandorlas. Unfortunately, the vault frescoes suffered more during the centuries than the wall frescoes. The walls and the vault are subdivided by decorative bands with rich figural and ornamental decoration.

In the frescoes of the St George Chapel, Altichiero appears as a master at designing architectural settings. He always gave his figures space, in the sense of room to move, along with this freedom of movement are their characteristic serenity and deliberate quality, which is strongly reminiscent of Giotto's figural ideal. Altichiero, notwithstanding his considerable originality, is indebted to Giotto more than any other artist.